The field of this invention is plant molecular biology. In particular, the invention relates to chimeric transcription regulatory sequences which promote target gene expression in a particular plant tissue, for example in root tissue or in reproductive tissue, by coupling regulatory elements of the bacterial lac operon with a strong plant promoter of choice.
There is a longfelt need in the art for organ-specific and tissue-specific plant regulatory systems, and especially for strong, tightly controlled root-specific transcriptional expression systems and for tightly controlled expression systems for other plant tissues, including reproductive tissue, such that controlled plant gene expression, including determination of conditional sterility, can be achieved. There is also a need in the art for phytoremediation strategies with improved sequestration of the target environmental pollutant, for example, mercury.